The invention relates to a substrate for substrate designed to support an object for processing, such as a substrate for a semiconductor element, wherein the substrate contains carbon and is designed to be porous so as to form gas outlet or gas passage openings. The invention further relates to a method for producing a substrate designed to support an object for processing, preferably a substrate for a semiconductor element such as a wafer, wherein the substrate is designed using carbon, giving it a level of porosity that allows the formation of gas outlet or gas passage openings.
Substrates of this type can be used, for example, in CVD processes. In such processes, the gas flow escaping from the substrate through gas outlet openings can ensure that autodoping by dopant atoms, which permeate the object, is prevented by the gas, which carries said atoms away (see U.S. Pat. No. 6,444,027).
In order to also clean the back surface of a flat object in a process chamber, according to U.S. Pat. No. 5,960,555 a susceptor is provided, which is equipped with openings via which the cleaning gas flows onto the back surface.
According to JP-A-10223545, a susceptor for a CVD arrangement is equipped with bored holes via which dopant atoms escaping on the back surface of an object to be doped from the front surface are carried away.
GB-A-2 172 822 relates to a porous support device comprised of fibers, through which air is suctioned for the purpose of holding a work piece in place.
To handle objects without contact with them, according to DE-A-101 45 686 a circular plate arrangement is proposed, which is equipped with through holes through which compressed gas is fed. Alternatively, open-pored materials can be used. Such materials can be of any type, such as, for example, glass.
In WO-A-03/049157 a transport device for wafers is described. The device is comprised of carbon fiber-reinforced material, which has on its surface an electrically conductive polymer, in order to prevent charging.
A susceptor according to JP-A-1 1035391 is comprised of a closed body made of carbon material. A corresponding susceptor is also described in US-A-2003/0160044, which is comprised of carbon and has a closed surface.
A susceptor of lower mass made of glassy carbon with a SiC coating is known from JP-A-08181150. The silicon carbide coating makes the susceptor gas impermeable.
According to JP-A-03246931, to allow the even distribution of heat a susceptor made of carbon material and carbon fibers is proposed, which is comprised of two mutually spaced plates. Bored holes extend in the hollow space that forms between the plates. In order to prevent contaminants from escaping from the base material, the surface is sealed with a SiC film.
In order to process a substrate, according to JP-A-09209152 the substrate is mounted on a ring made of a carbon fiber-reinforced material, which is provided on the outer surface with a SiC coating.
A susceptor made of porous carbon is disclosed in JP-A-60254610.
A suction device according to JP-A-2000031098 provides for a body made of synthetic resin, carbon and ebonite, with vertically extending pores designed to fix an object on the substrate material by means of vacuum pressure.